This invention relates to an improvement of a damper device having a cylinder body and a piston body, at least either one side of which is attached to an article subject to damping, whereby damping is applied to the movement or relative movement of the article subject to damping.
There is an air damper having a piston and a cylinder, and including a stepped hole comprising a cylindrical hole and a conical hole formed on the closed one end of the cylinder, and being made so as to close this stepped hole with a rubber plate having a center hole from the outside of the cylinder (see Patent Document 1: Publication of Japanese Examined Patent Publication No. H4-48658 from page 2, column 4, line 33 to page 3, column 5, line 4). In such air damper, the rubber plate is drawn inside the conical hole of the stepped hole by the negative pressure caused inside the cylinder by the retreat of the piston and its center hole is made to contract whereby the retreat of the piston is made more difficult (that is, damping force is applied to the retreat of the piston).
However, in such air damper, because it is difficult to closely set the extent of contraction of the center hole of such rubber plate, it is difficult to set said damping force to the desired size, also, when the rubber plate deteriorates over time, the damping force changes. Also, in an automobile glove compartment, or the like, in order that a change is not caused in the speed of opening between when the weight of the articles stored inside is light and when it is heavy, it is required that such speed of opening be made roughly constant by this kind of air damper regardless of the weight or presence of articles stored inside.
The main problem that this invention attempts to solve is to easily perform setting of the damping force in this kind of damper device, and to exercise the set damping force stably over a long period. Also, when such damper is used in an automobile glove compartment, or the like, the speed of opening of such glove compartment, or the like, is always made roughly constant regardless of the weight or presence of articles stored inside.
Further objects and advantages of the invention will be apparent from the following description of the invention.